Navigating Dermatofibrosarcoma Protuberans: Understanding, Treatment, and Support

What Is Dermatofibrosarcoma Protuberans?

Dermatofibrosarcoma protuberans refers to a rare skin tumor that involves the dermis, subcutaneous fat, and muscle and fascia in rare cases. This tumor typically clinically manifests as a slowly growing, firm plaque on young adults' arms, legs, and trunks. The exact cause of dermatofibrosarcoma protuberans needs to be clearly understood. However, studies have suggested a chromosomal translocation, resulting in the fusion protein COL1A1-PDGFB, which facilitates tumor growth by overproduction of platelet-derived growth factor (PDGF).

What Are the Different Types of Dermatofibrosarcoma Protuberans?

Several variants of dermatofibrosarcoma protuberans exist involving different cell types.

These variants include:

• Pigmented Dermatofibrosarcoma Protuberans (Bednar Tumors): These tumors include pigmented cells called melanin-containing dendritic cells.

• Myxoid Dermatofibrosarcoma Protuberans: These tumors contain an abnormal type of connective tissue called the myxoid stroma.

• Juvenile Dermatofibrosarcoma Protuberans (Giant Cell Fibroblastoma): These tumors typically affect children and adolescents and are marked by giant cells in the tumor.

How Common Is Dermatofibrosarcoma Protuberans?

Dermatofibrosarcoma protuberans is a rare tumor that accounts for between 1 to 6 percent of all soft tissue sarcomas and 18 percent of all cutaneous soft tissue sarcomas. It has an incidence rate of 0.8 to 4.5 cases per million persons per year. Bednar tumor accounts for less than 5 percent, and the fibro sarcomatous variant represents 5 to 15 percent of all dermatofibrosarcoma protuberans cases. Dermatofibrosarcoma protuberans mainly occur in adults in the third to fifth decades of life but can occur at any age. During pregnancy, dermatofibrosarcoma protuberans can demonstrate accelerated growth. Dermatofibrosarcoma protuberans, especially Bednar tumors, occur most often in black people.

What Causes Dermatofibrosarcoma Protuberans?

The actual cause of dermatofibrosarcoma protuberans is still unknown; it is believed to originate from a dermal stem cell or undifferentiated mesenchymal cell with fibroblastic, muscular, and neurologic features. Possible risk factors include trauma or injury to the skin in the affected area. In addition, occurrences of this tumor within preexisting scars and tattoos have been reported. Recent advances show tumor cells have abnormal chromosomes within the tumor cells, resulting in the fusion gene COL1A1-PDGFB. This gene encodes a protein that causes a tumor to grow by autocrine overproduction of platelet-derived growth factor (PDGF).

Who Is More Likely to Get Dermatofibrosarcoma Protuberans?

Dermatofibrosarcoma protuberans is uncommon and affects less than one person in every 100,000 inhabitants annually. It usually occurs in early or middle adulthood between 20 and 59 years of age, but it can happen at any age. This tumor is rarely seen in children. Men are slightly more affected than women.

What Are the Main Signs and Symptoms of Dermatofibrosarcoma Protuberans?

The dermatofibrosarcoma protuberans typically starts as a small, firm patch of skin, usually 1 to 5 centimeters in diameter, reddish, purplish, or flesh-colored. The tumor grows slowly and later becomes a raised nodule. Occasionally, the tumor starts as a flat or depressed skin patch (plaque). The tumor, especially in the initial stages, can resemble a keloid or dermatofibroma and is often misdiagnosed.

Most tumors are located on the trunk, followed by arms, legs, head, or neck. Affected people usually initially show signs of this condition in their thirties. However, the age at which a tumor appears varies widely. Dermatofibrosarcoma protuberans typically extend into the subcutaneous fat but rarely involve the fascia, muscle, or bone unless it is recurrent or longstanding. Dermatofibrosarcoma protuberans have relentless growth with asymmetric, root-like projections that cannot be appreciated clinically. Thus, local recurrence after excision is common. Distant metastasis (spread) is rare in 1 to 4 percent of cases and generally only after multiple local recurrences.

How Is Dermatofibrosarcoma Protuberans Diagnosed?

Diagnosing dermatofibrosarcoma protuberans is based on a physical examination and medical history. The healthcare provider inspects the affected skin to look for signs of the tumor and performs a lymph node examination.

Other tests and procedures used to diagnose dermatofibrosarcoma protuberans include:

• Skin Biopsy: This involves removing a small amount of tissue for testing. Tests in the laboratory can see if cancer cells are present.

• Imaging Tests: Chest imaging may be ordered to evaluate for any metastatic disease before treatment, though this is not a general recommendation. Preoperative magnetic resonance imaging (MRI) is sometimes performed to check tumor extension before surgery.

How Are Dermatofibrosarcoma Protuberans Treated?

The mainstay of treatment for dermatofibrosarcoma protuberans is surgical removal, ideally with Mohs micrographic surgery (MMS). However, other therapies to kill cancer cells remain after surgery. These treatments include:

Surgery to Remove the Cancer: The healthcare provider may suggest a surgical procedure to remove cancer and some healthy tissue around it. This procedure makes it more likely that all the cancer cells are removed.

• Mohs Surgery: This surgical technique removes thin layers of cancer-containing skin until only cancer-free tissue is left. After removing each layer of the skin, it is examined under a microscope for cancer cells. This process continues until there are no signs of cancer. Mohs surgery may help treat larger cancers. Unfortunately, dermatofibrosarcoma protuberans grow irregularly, making it difficult to remove altogether.

• Targeted Therapy: Targeted therapy drugs attack and block specific chemicals in cancer cells. This causes cancer cells to die. Some individuals with dermatofibrosarcoma protuberans have cancer cells that make an excess protein. Imatinib has been approved by the U.S. Food and Drug Administration. However, targeted therapy is meant to treat every person with dermatofibrosarcoma protuberans; the provider may recommend this treatment if cancer returns after surgery or has spread to other body parts. In some people with advanced dermatofibrosarcoma protuberans, Imatinib Mesylate may be taken before surgery to reduce the tumor size and make surgery more effective. Using a combination of medication and surgery to treat advanced dermatofibrosarcoma protuberans can significantly reduce the risk of DFSP returning.

• Radiation Therapy: Radiation therapy utilizes powerful energy beams, such as X-rays and protons, to destroy cancer cells. The healthcare provider may suggest radiation therapy if all cancer cannot be removed during surgery. However, due to the long-term risks involved in receiving radiation treatments, providers carefully consider this treatment's benefits and risks.

Local recurrence is common, so close clinical follow-up after treatment is essential. The risk of recurrence is highest in the first three years after treatment. Therefore, people with this tumor should be evaluated every three to six months annually.

What Is the Outlook or Prognosis for People With Dermatofibrosarcoma Protuberans?

The general prognosis of dermatofibrosarcoma protuberans is usually excellent, with a 10-year survival rate of 99.1 percent. However, because metastasis is rare, morbidity due to local recurrence is a more common problem. Age above 50 is a risk factor for local recurrence. On average, people with the metastatic disease live about two years after diagnosis. A high mitotic index, black race, male sex, increased cellularity, and location on the head, neck, or trunk are risk factors for higher mortality rates. A poor prognosis is related to metastasis. However, recent results for people with metastasis using Imatinib are promising.

What Are the Complications of Dermatofibrosarcoma Protuberans?

While the overall prognosis for dermatofibrosarcoma protuberans is quite good, the major complication is the rare cases where it can metastasize. Other complications include post-surgical scarring and cosmesis.

Conclusion:

Dermatofibrosarcoma protuberans refers to a rare skin tumor that involves the dermis, subcutaneous fat, and muscle and fascia in rare cases. The preferred treatment of dermatofibrosarcoma protuberans is surgical removal. Other treatments like targeted drug therapy and radiation therapy. Because local recurrences are common, close clinical follow-up after treatment is essential.